JP 2005-348193 A (PTL 1) discloses an electronic device, such as a mobile phone or the like, that transmits air-conducted sound and bone-conducted sound to a user. As the air-conducted sound, PTL 1 discloses a sound that is transmitted to the user's auditory nerve by air vibrations, caused by a vibrating object, that are transmitted through the external ear canal to the eardrum and cause the eardrum to vibrate. As the bone-conducted sound, PTL 1 discloses a sound that is transmitted to the user's auditory nerve through a portion of the user's body (such as the cartilage of the outer ear) that is contacting a vibrating object.
In the telephone disclosed in PTL 1, a rectangular vibrating body, formed from a piezoelectric bimorph and a flexible substance, is attached to an outer surface of a housing via an elastic member. PTL 1 also discloses that when voltage is applied to the piezoelectric bimorph in the vibrating body, the piezoelectric material expands and contracts in the longitudinal direction, causing the vibrating body to undergo bending vibration. Air-conducted sound and bone-conducted sound are transmitted to the user when the user touches the vibrating body to the auricle. The applicant has also developed a mobile phone that, unlike the mobile phone disclosed in PTL 1, causes a panel, such as a display panel or protective panel disposed on a surface of the mobile phone, to undergo bending vibration due to a piezoelectric element, and that transmits sound using air-conducted sound generated by the bending vibration and vibration sound, which is a sound component due to vibration transmitted when the vibrating panel is pressed against a human ear.